Controls on Periodicity of CO2-Driven Cold-Water Geyser Eruption through Abandoned Well: Tenmile Geyser in Utah
Abstract
One of the primary concerns of geologic CO2 sequestration (GCS) is that stored CO2 leaks to the surface through unexpected pathways such as abandoned wells. As a natural analog of CO2 leakage from geological storage facilities, CO2-driven cold-water geysers, with less than 20 occurrences worldwide, became a reference to infer the CO2 leakage mechanisms. The CO2-driven cold-water geysers periodically eject relatively cold water (< 20 ºC) mainly through man-made wells drilled into natural CO2 reservoirs in a deep formation. Although upward CO2 bubbles can explain the erupting process with amalgamation and expansion, the trigger point and the changes of the eruption cycle are still in the mist. A time-series dataset from 132 naturally driven geyser eruptions in 2011, 2013, 2014, and 2015 were collected at Tenmile well in Utah, where CO2-rich water was fed from Navajo Sandstone. The measurement data identified the eruption duration (ED) and interval between two consecutive eruptions (IBE) by the pressure changes. The means of ED and IBE were counted as 9.76 ± 0.10 min and 8.42 ± 0.21 hr, respectively, indicating that IBE occupied the main portion of each cycle. To find the trigger point of geyser eruption, hydraulic pressure was forcibly decreased four times. Then, four artificial eruptions were evolved when the pressure decreased by 7.27 kPa, 11.08 kPa, 11.33 kPa, and 14.41 kPa. For the naturally driven eruptions, such slight reductions in hydraulic pressure were already initiated during IBEs. Additionally, the pressure drop rate was significantly influenced by the atmospheric pressure (Pair) and temperature (Tair), so the length of IBE was determined by the variations in both Pair and Tair. For example, IBE was shortened at low Pair and high Tair; IBE was lengthened at high Pair and low Tair. Because of considerable daily variations in Pair (5.46 ± 0.22 kPa) and Tair (22.25 ± 1.51 °C) in the study area, the lengths of IBEs showed significant fluctuations from min of 3.90 hr to max of 15.74 hr. These findings indicate that the prolonged specific climate conditions (i.e., low Pair and high Tair) will accelerate CO2 transfer from the geologic formation to the atmosphere through the well.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFMGC15D0711P